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From "Michael McCandless (JIRA)" <>
Subject [jira] [Commented] (LUCENE-3209) Memory codec
Date Fri, 17 Jun 2011 11:52:47 GMT


Michael McCandless commented on LUCENE-3209:

Woops!  I forgot about LUCENE-3069, but, yes this is very similar.

But I think one difference is LUCENE-3069 aims to have all terms memory resident but postings
would still reside in the Directory, I think?  Whereas my patch here puts all terms and postings
in RAM (in a single FST).  The postings format is similar to what PulsingCodec does, ie, doc
+ tf + pos + payload are all serialized into a single byte[] using delta vInts.

So I think we should keep LUCENE-3069 open, as an enhancement to this codec to make it separately
controllable whether postings should also be in RAM?

> Memory codec
> ------------
>                 Key: LUCENE-3209
>                 URL:
>             Project: Lucene - Java
>          Issue Type: Improvement
>          Components: core/index
>            Reporter: Michael McCandless
>            Assignee: Michael McCandless
>             Fix For: 4.0
>         Attachments: LUCENE-3209.patch
> This codec stores all terms/postings in RAM.  It uses an
> FST<BytesRef>.  This is useful on a primary key field to ensure
> lookups don't need to hit disk, to keep NRT reopen time fast even
> under IO contention.

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